Manufacture of artificial silk



, disadvantages most Patented I Jan. 5, 1932 UNITED STATES; PATENT oFFics 1 WILLIAM F. RICHTER, OF APOLLO, PENNSYLVANIA, ASSIGNOR TO CHEMICAL HOLDING 5 CORPORATION, or APOLLO, PENNSYLVANIA,

MANUFACTURE or ARTIFICIAL sir.

N 0 Drawing.

This invention relates to the manufacture ficial silk heretofore prepared from Wood 10 P p Other objects and advantages of this invention will become apparent during the course of the following description.

As is well known, repeated efforts have been made to improve the quality and finish of artificial silk sothat it will possess certain of the advantageous properties of natural or. real silk which it does not now possess. These efforts have been successful to a marked degree but the desired goal has not as yetbeen reached. For example, artificial silk made from wood pulp lacks to a certain degree the softness of texture or feel and fiber resonance or sound possessed by real silk. In some instances the in these desirable acterized as harsh and dull.

In order to overcome the above referred to processes of manufacturing artificial silk from wood pulp as heretofore employed have been variously modified but such modifications have met with only partial success. It is the principal purpose of this invention to provide an eflicient and at the same time a simple process of manufacturing from wood pulp artificial silk which approaches real silk in the properties of sound and feel.

I have discovered that artificial silk possessing the desirable properties referred to as well as the desirable properties now possessed by artificial silk prepared from wood pulp in the conventional duced by mixing with the wood pulp prior to chemical treatment in process very finely divided cotton, preferably in the form of cotton dust. Cotton dust is particularly advantageous for use since it produces the desired results and is very cheap considered to artificial silk is so-lacking properties thatit is char-- or such mixture together manner may be pro-.

the manufacturing A CORPORATION OF DELAWARE Application filed June 27, 1929'. Serial No. 374,276.

raw material and one which is ordinarily be'a Waste product. 7 I In the preferred practice of my process I first mix with any suitable wood pulp, such actual amountof cotton dust employed may be varied to a substantial extent but I have found that a mixture of ingredients consisting of from 85 to 95 per cent. wood pulp and from 15 to 5 per cent. of cotton dust produces the best results. In commercial practice from about five to eighteenpounds of clean cotton dust is mixed with approximately one hundred pounds of, sulphite pulp. V V After the wood pulp and finelydivided cotton have been mixed together, the mixture is then treated, according to any of the conventional processes of making artificial silk. For example, the" mixture may be treated ac cordingto the so-called viscose process in any of its modified forms. Sinceany o f'the commercial practices of preparing rayon from cellulose fiber may be employedin the mann facture of artificial silk from the rawma te--- rial consisting of wood pulp and cotton'dust,

with other cellulose er, it is unnecessary to specifically outline any-particular manufacturing process. In. the ordinary viscose process the raw material is first converted into an alkali cellulose which is drained, pressed and ground into relatively finely divided form, after which the resulting material is treated with carbon di-, sulphide in a suitable xanthating apparatus. The viscous mass produced isthen ordinarily thinned and further digested with caustic after-which it is filteredand aged. The aged material is then spun into a setting bath'from a suitable spinnerette. This spun material" after washing, bleaching and drying. treatment is finallyformd into finished filaments or threads of artificial silk. V

hen the artificial. silk is prepared according to my'process it possesses a remarkable softness of texture or feel and also a superior sound. In addition my experiments indicate that the silkpossesses a somewhat increased dry strength although the im i provement in sound and feel is the most poplar or. spruce pulp a minor proportion" of'cotto'n dust. The

noticeable and important result. The exact cause of the improvement in the quality of the silk due to the use of cotton dust as described is not definitely known but it appears 5 that the cotton dust adheres to the long fiber in the wood pulp in the beginning of the process and remains in association therewith during the process. However, regardless of the exact cause of the improved results, ex" l'tensiv'e experiments and tests clearly demonl strate that-the results are obtained and are directly dueto the use of the cotton dust in conjunction with the wood-pulp.

While the use of cotton dust is particularly advantageous in conjunction with w'ood'pulp a certain measure of success may beobtained V 'by em ploying cotton dust in conjunction with other cellulosefibers, particularly those which are structurally similar to the wood pulp fiber. However, no improved results are no- I ticed when the cotton dust is used in conjuncvtion with cotton linters and therefore this procedure is notirecommended. V l i WVhile I have described in detail-the preierred practice of my process it is to be understood that the detailsof procedure'may be. modifiedwithout departing from the spirit pf the invention or the scope of the subjoined claims. What'I claim is: V V

In the production of viscose from wood pulp and structurally similar cellulose fibers, I the step offormingalkali cellulose by treatvinent of a mixture of a major proportion of V said pulp and a minor proportion of cotton idust withfan alkali, the cotton dustfibers beingsubstantially shorter than those oi said 2. In the production of viscose from wood,

pulp,"thestep of forming alkali cellulose by treatment of a mixture of about95 to 85per 7 cent of said pulp, and about 5 to 15 per cent of ."cotton dust, with an alkali. i p 7 p i a i 8. A process of making alkali cellulose; comprising mixing wood pulp with a minor fproportion of cotton dust, and subjecting V said'mixture to a solution of caustic soda. 7

A raw material for use in the prepara-' r tion of alkali cellulose, vcomprising a 'mixture of wood cellulose fiber and cotton dust,

said wood fiber constituting the preponderant portion of said mixture and its fibers being substantially longer than those of said cotton dust. v r V y a 5. A raw material for use the preparation of alkali cellulose, comprising a mixture otabout to 85 percentlof wood pulp and 5 to per cent of cotton-dust. 7

; ,In testimony whereofiI' aflix my signature.

} seq I WILLIAM RICHTER; 

